Reposted from the Cliff Mass Weather Blog
Twice today I was asked about the difference between partly cloudy and partly sunny. And that inquiry is one of the most frequent I get, for reasons I do not understand.
OK…let’s settle this for once and for all.
Here is an image of a partly cloudy sky:
And here is an image of a partly sunny sky:
They are the same.…. during the day, partly cloudy and partly sunny denote exactly the same thing: a sky with between 3/8 and 5/8 coverage of clouds. Obviously, partly cloudy would be a better choice at night.
Mostly cloudy is 5/8 to 7/8 coverage, while mostly sunny indicates 1/8 to 3/8 coverage during the day.
Now, a harder one. What does it mean to have a sky obscured? Is it the same as an overcast sky?
The answer to the second question is NO–they are not the same.
The sky is obscured when you can not see the sky, when you are in middle of cloud or smoke or dust storm. Here are two examples of an obscured sky, one from smoke and the other from low clouds/fog:
An overcast sky is when the entire sky is covered by clouds or smoke, but you are not in them. You can see the base (bottom part) of the clouds or smoke. Here is an example:
With this knowledge, you can amaze your friends at the next cocktail party…. whenever cocktail parties start again.
People will be “cootie conscious” for months, paranoid. I am near Detroit, and 4 years ago I got what I think was viral bronchitis from kissing a woman who brought it back from Istanbul a month earlier, she had no symptoms. Ya gonna get sick once in a while.
Would it be the same as the difference between an optimist and a pessimist?
Depends on the size of the glass.
So … the question is, “Is the sky half-empty or half-full?” 😎
Thanks Cliff.
Now that those things have been cleared up, why is the planet’s ECS postulated to be 1.5C to 4.5C?
Surely after ~40 years of research, and more CO2 in the air, we could be told a more precise range?
“Tonights forecast is dark. Continuing dark throughout the night, with widely scattered light in the morning.”
— The Hippy Dippy Weatherman, George Carlin
@Cliff – For the next weather trivia, please do “chance of rain.” (Keep on having to explain to people that “50%” does not mean it will rain right here for half the day. Especially right here – some monsoon seasons, my neighborhood seems to have a rain shield around it…)
When I was an Air Traffic Control Tower Operator trainee, in 1968, at Lowe Army Airfield, Ft. Rucker, Alabama, we had a morning of: W0X0F (W-zero-X-zero-F). This was sky obscured, zero vertical visibility, zero visibility, fog. We could not see the ground from the tower, Then a helicopter starts up, in comes an IFR flight plan, with the pilot properly instrument certified, he calls, is cautioned about W0X0F, and takes off. Heard the sound but never saw him.
Does “Partly Moony” mean the plumber is here?
If they are the same why are they different?
Seriously this is the kind of triviality that annoys the crap out of people. Not that Partly Sunny is the same as Partly Cloudy, but rather that there are over educated wetwipes who revel at knowing this nonsense and correcting people that don’t.
What’s the difference between geothermal heat flux and insolation?
http://phzoe.com/2020/05/22/equating-perpendicular-planes-is-plain-nonsense/
overcast, broken, scattered, few clouds, clear below 12,000
My late father was, before he retired, the top instrument rated prop pilot (he did not transition to jets) in the USAF. He was also sent by USAF to UCLA for two masters degrees in 1946. One in meteorology, and one in electronics (Weather radar). Then flew weather recon for three years off Guam as Commander of the 409th typhoon chasers squadron using modified B-29 aircraft (Bombays converted to lots of radar instrumentation and dropsondes). Very earliest serious tropical storm/typhoon research in the Pacific.
He used to tell weather jokes like Cliff’s partly cloudy/partly sunny nondifference around the dinner table. A feeble but fond memory example follows.
All a meteorologist really needs to diagnose present weather is a good weather string.
If you can see its shadow, its sunny.
If you cannot see its shadow, its cloudy.
If you cannot see it at all in daytime, its foggy.
If it isn’t hanging vertically, its windy.
If it is wet, its raining.
And so on.
Then he would say—Diagnose the weather for tomorrow is much more difficult. Strings won’t help.
When I was living in Buffalo, NY, a common weather forecast was for “a mix of sun and clouds.” And true enough, it was a hazy day. Take the top two pictures in this post and stir.
Buffalo has never been known for nice weather.
Partly sunny is with a cloud bias. Partly cloudy is with a sun bias. Each approaches a limit from a different starting point.
Tomato, tomahto. Let’s call the whole thing off.
The partly sunny became popular back in the early 1970s, as best I recall. Some busybody weather personality decided partly sunny was more cheery that partly cloudy. All the meteorologists I knew at the time kept on with the usual partly cloudy line, but not so the radio/TV personalities.
Partly cloudy…partly sunny. That reminds me of the story of the Indian Chief visiting London for a University conference on Language. The words being discussed were Complete and Finish. All the professors and experts agreed the meaning of the two words were essentially the same, and even the dictionary says as much.
The wise old Indian Chief stood up, spoke and said; When you have a good woman you are complete. When you have the wrong women, you are finished. And when the right woman catches you with the wrong woman, you are completely finished!
During the Second World War radio announcers could not talk about the weather. So when the base ball game was rained out the announcer said, “Folks, the game has been cancelled. I can’t tell you why, but if you stick your head out the window, you’ll figure it out.”
Cliff,
so far in the comments we have had optimist, cliff and low cloud.
so here is my story, combining all three.:)
In the late 70s, I was a soldier on the tiny island of st Kilda,50 miles off the outer Hebrides in Scotland. one day I wandered out of the radar station for a stroll along the 600 feet cliffs and a cloud, or mist , or fog came down and I was stuck. all I could hear were the crashing waves, I could barely see my hand in front of my face. I was feet from the cliffs edge and I was completely disorientated.
I sat down straight away. one false move and I was over the edge.
Made a little circle of stones, like a clock face.
Then I threw a pebble at 12 oclock. one oclock and so on.
I moved towards 12 till one of the pebbles made no sound. the cliff edge. moved in the opposite direction and eventually the pebble hit a wall. I was saved. there are lots of pebbles on that island
When I think it’s partly sunny, CNN says it’s partly cloudy
and
vica versa.
I think that to the average person simply reacting to the words, partly cloudy would imply sunny with some clouds, and partly sunny would imply cloudy with some sun. Although they are the same, the connotation is that one would have more sun than the other.
More interesting might be the basic question, what the relation between cloudiness and temperature is. Is it warmer with or without clouds? A question of fundamental importance to all climate “science”, which every weather guy should easily be able to answer.
Spoiler alert! I checked it out for myself, here with the example of the Aleut Islands, where according to NASA cloud forcing is meant to be massively negative.
Seasonally resolved:
Annual average:
I’ve always felt that Partly Sunny was the same as Mostly Cloudy, and that Partly Cloudy was the same as Mostly Sunny. I don’t see Partly Sunny and Partly Cloudy as the same at all.
Pay attention because the weather forecast is going to change, often and at short intervals.
But climate models can tell us what the weather is going to be like 50 years from now /sarc